This dose finding study uses a 3 + 3 dose escalation and expansion design to establish the recommended Phase 2 dose (RP2D). Treatment will consist 28 day treatment cycles with a single Rituximab infusion per cycle for 6 cycles and twice daily (days 1-28) administration of CC-292 with a starting dose cohort of 375mg twice a day. Following safety review of the data from the initial cohort and confirmation that the initial dose is tolerable, the next dose level will be enrolled with a once per cycle Rituximab infusion for 6 cycles and twice daily CC-292 at 500 mg.